slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Synthesis and characterisation of thin film MAX phase alloys PowerPoint Presentation
Download Presentation
Synthesis and characterisation of thin film MAX phase alloys

Loading in 2 Seconds...

play fullscreen
1 / 1

Synthesis and characterisation of thin film MAX phase alloys - PowerPoint PPT Presentation


  • 114 Views
  • Uploaded on

Figure 2. Pulsed cathodic arc at the University of Sydney. Figure 4. Al/C pulse ratio vs the Al/C film composition ratio from SNMS. The linear relationship establishes a quick and reliable method for accurately controlling and quantifying the composition of thin film MAX phases.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

Synthesis and characterisation of thin film MAX phase alloys


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Figure 2. Pulsed cathodic arc at the University of Sydney

Figure 4. Al/C pulse ratio vs the Al/C film composition ratio from SNMS. The linear relationship establishes a quick and reliable method for accurately controlling and quantifying the composition of thin film MAX phases.

Synthesis and characterisation of thin film MAX phase alloys

Mathew Guenette, Mark Tucker, Yongbai Yin, Marcela Bilek, David McKenzie

Applied and Plasma Physics, University of Sydney 2006, Australia.

guenette@physics.usyd.edu.au

Introduction

MAX phases are a family of ternary alloys that exhibit a unique combination of metallic and ceramic properties. That is, machinablility, resistance to thermal shock, high thermal and electrical conductivity combined with stiffness, oxidation resistance and high temperature (T>1400°C) stability.

The nanolaminate crystal structure of the MAX phases consists of single hexagonal layers of the A element between metal-carbide or metal-nitride (Mn+1Xn) layers.

http://www.materials.drexel.edu/max

H. Högberg et al. Surface & Coatings Technology 193: 6–10, 2005

Figure 1. General Mn+1AXn phase composition (n=1,2,3) and unit cell

X-ray Diffraction

XRD scans of near stoichiometric Ti2AlC reveal a highly oriented, relatively phase pure thin film. The θ/2θ scan in Fig.5 shows strong reflections only from Ti2AlC(00ℓ) planes demonstrating preferred c-axis oriented film growth. Oriented TiC(hhh) reflections are also observed. The glancing angle scan reveals only Ti2AlC peaks demonstrating a highly phase pure film.

Pulsed cathodic arc MAX phase synthesis

and SNMS composition analysis

Deposition of Ti2AlC thin film on Al2O3(0001) at a temperature of 900°C was carried out using a high current, centre triggered, pulsed cathodic arc fitted with three cathodes (Ti, Al and C) (Fig. 2). The film composition can be accurately controlled by varying the number of pulses of each element. A linear relationship between the number of pulses from the cathodes and the composition of the film is observed over the order of 10 000 to 100 000 pulses (Fig. 4).

Due to cathode erosion with deposition, long term drift in the composition of deposited films occurs. Film composition is affected by changes in substrate temperature and bias due to different mass and volatility between elements. Correct stoichiometry is vital to successfully synthesise MAX phases and a method for rapid tuning of film composition is required.

a)

Figure 3. SNMS chamber

Secondary Neutral Mass Spectrometry (SNMS) is a fast and convenient plasma technique which can be used to analyse the composition of a thin film. The film is sputtered with an argon plasma and the composition of the emerging neutral particles is measured with a mass spectrometer. The elemental ratio within the sample is directly proportional to the ratio of the SNMS signal intensities. Quantitative analysis of films is possible by comparison to standards of known composition.

b)

Figure 5. a) θ/2θ XRD scan b) glancing angle XRD scan (incident angle = 0.6°)

  • Conclusion
  • A method for accurately controlling and quantifying the composition of thin films grown in the pulsed cathodic arc has been established.
  • This method has been used for the growth of highly oriented and phase pure Ti2AlC suitable for measurement of non-isotropic properties such as elastic constants and electrical conductivity.